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(No Model.) 3 Sheets-Sheet 1.

S. SGHUGKERT & G. MUNKER. MACHINE 1 0R GRINDING AND POLISHING PARABOLIC, 0R ANALOGOUS OURVILINEAR SURFACES.

No. 537,126. I Patented Apr. 9, 1895.

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3 Sheets-Sheet 2.

S. SOHUCKERT & G. MUNKER. MACHINE FOR GRINDING AND POLISHING PARABOLIC OR ANALOGOUS GURVILINEAR SURFACES.

N0. 537,126.v Patented Apr. 9, 1895.

(No Model.)

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. S. SGHUGKERT & GVMUNKERF MACHINE FOR GRINDING AND POLISHING PARABOLIC 0R ANALOGOUS GURVILINEAR summons.

No. 537,126. Patented Apr. 9,1895.

(No Model.)

NITED STATES P TE T OFFICE,

SIGMUND SOHUCKERT AND GEORG MUNKER, OF NUREMBERG, GERMANY.

MACHINE FOR GRINDING AND POLISHING PARABOLIC OR ANALOGOUS CURVILINEAR SURFACES.

SPECIFICATION forming part of Letters Patent No. 537,126, dated April 9, 1895.

Application filed January 10, 1894- gerial No. 496,433- (No model.) Patented in Germany August 18,1885 No. 35,477: in England October 22, 1885,11'0. 12,684i in France October 24,1885, No. 171,849; in Italy December 31, 1885, XIX, 19,058, XXXVII, 345, and in Austria Hungary May 1, 1886, No. 38,294 and No. 66,352-

T0 on whom it may concern.-

Be it known that we, SIGMUND SoHUoKEaT gust 18, 1885, No. 35,477; France, October 24,"

1885-, No. 171,849; England, October 22,1885, No.12,684; Austria-Hungary, May 1, 1886, No,

- 38,29 1 and No. 66,352, and Italy, December 31,

1885, Vol. XIX, No. 19,058, Vol. XXXVII, No. 345;) of which the following is a specification. It is Well known by those who use curviline ear reflectors in connection with illuminants, such as electric arc lamps, calcium lights and thelike, that the best results are attained only when such curvilinear surfaces so used approach perfect paroboloids, hemispheres, hyperboloids or the like, dependent upon the type of the surface to be so used, paraboloids being more generally used than the others named.

Our invention has for its object the construction of paraboloidal or analogous curvilinear mirrors which shall approach or approximate perfect curvilinear surfaces in order that when the illuminant,- such as an arc lamp or the like, is located at the focus all of the rays of light will be reflected in some constant relation. We accomplish this object by the use of'apparatus difierent forms of which are hereinafter illustrated and described, the especial features of novelty claimed by us as of our invention being particularly pointed out in the claims at the end of this specification. Referring now to the drawings in all of which like letters of reference and numerals represent like parts wherever used, Figure 1 is a diagrammatic view illustrating the generic principle upon which our invention is based. Fig. 2 is a side elevational view of one form of our improved mechanism illustrating the surface to be operated upon and its sustaining parts in section. Fig. 3 is a plan view of the same form of' the entire apparatus, and

Fig. 4 is a side elevational view of the same as will now proceed to describe.

seen looking at Fig.2 from the right toward the left side of the drawings. are detail views of our preferred form of grinding and polishing tool, together with the arm or holder which attaches it to the carriage or controlling mechanism. Fig. 7 is a side elevation of a. modified form of the device shown in Fig. 2.

The essential principle of our invention is based upon the following property of the parabola: Referring first to Fig. 1 of the drawings, let a; be any point in a parabola; as y, the

axis of said parabola; 0, its focus; yy', a lineperpendicular to the axis x y, and oc'y a line parallel to the latter. Under this condition of affairs 0 oa+x y=0 w'|m y. If, now, a cord of the length of 0 a2+00 y be fixed at one end at 0 and its other end be movedin the direction of the straight line y y the cord being stretched by a pencil or other rigid point so that the part 11 0c always remains parallel with the axis a: y, then said point describes a parabola having a focal distance 0 00. It, now, one end of the cord be fixed to the circumference of a fixed disk 8 whose axis passes through the focus 0 and the cord be stretched by a movable disk 8' of equal size under the conditions above stated while the other end of said cord moves upon a straight line y y the center of the movable disk will describe the same parabola as that before mentioned.

Our improved apparatus for carrying into effect the principle of generating a curvilinear surface of paraboloidal or analogous form upon the principle disclosed in connection with the description of Fig.1 of the drawings is illustrated in Figs. 2, 3 and 4 which we 1 is a vertical shaft-journaledin a standard secured to the base of the machine and carrying a driving pulley for rotating it, together with a support 2 for the object or surface to be acted upon, which material is secured to said support in any preferred manner. 3 is a horizontal guide-way secured at its opposite ends to a pair of upright standards which in turn are fixed to the base, as clearly shown in Figs. 2 and 4:. 4: is'a carriage having lateral sliding motion in the horizontal guide-way 3 through the agency. of a screw which is journaled in Figs. 5 and 6 the opposite sides of the frame and is provided with a fixed and loose pulley, the former of which is adapted o rotate the screw and impart motion to the carriage &. 5 is a tool holding arm adapted to move vertically through grooves in the carriage 4. 23, Fig. 2, is a rotary tool carried at the lower end of the tool holding arm 5. Nearthe middle of the horizontal guide-way 3 is secured a disk 6 which is hollowed out upon one side as shown. Journaled to oneside of the vertically moving tool holding arm 5 is a pulley 7 of the same diameter as the fixed disk 6. 6 is a steel hand, one end of which is secured to a pin 8 after which it passes around the disk 6 and over the pulley 7, the other end being secured to the carriage 4 by an adjustable eccentric 9 so as to put it under proper tension. 10 is a bracket secured to the upper end of the guide-way and carrying two grooved pulleys 11 and 12 capable of being turned about a common axis upon which they are journaled. 13 is a counter-weight attached to a belt passing over the pulley 11 and secured atits other end to the tool holding arm 5, the function of this counter-weight being to counter-balance with the desired nicety the tool holding arm and its attached parts. The grooved pulley 12 is eccentric or camshaped and acts as a support for an additional counter-weight 14; secured to a band and to the pulley. This pulley 12 with its counter-weight 14 serves to keep the steel band 6 under equal tensions at all positions. The operation of this form of the device is as follows: The surface to be ground being placed in position on the holder 2, as shown in the drawings, the belt is shifted from the loose pulley to the fixed pulley. This gives rotation to the driving screw 51 in such direction as to cause the carriage 4 to move from left to right in Fig. 2, thereby causing the tool-holding arm 5 to move from left to right and carry with it the rotating tool 23. As these parts move from left to right, the steel band 6 is slackened proportionately as the point 9 approaches the fixed disk 6. This slackening of the band permits the weights 13 and 14: to raise the tool-holding arm 5 and cause the pulley 7 and the tool to travel in the path of a parabola, corresponding to that of the surface on the holder 2.

Referring now to Figs. 5 and 6 for a detail description of the preferred form of tool and support, 5 is a tool holding arm, to the lower end of which is journaled a disk 16 which in turn supports, through the agency of a pivot 17, a ball joint consisting of two parts 18, 19, the latter of which supports the tool 20; 21, 21 being yielding springs adapted to adjust the tool to the surface to be acted upon. It is apparent therefore that by virtue of the universal action of the joints between the disk 16, pivot pin 17 and spherical joints 18, 19, the tool will adjust itself to meet the emergencies of the case. We prefer to use this improved form of tool to complete the operation, the crude or earlier portion of the work being performed by the rotary roll or tool 23 shown in Fig. 2 which consists of a hard steel or equivalent disk journaled to the lower end of the tool holding arm 5. This tool 23 is given rotary motion by a belt or pulley or any other preferred means.

In Fig. 7 a modification of the above described mechanism for guiding the tool is shown. In this figure, 22 is a curved guidebar having the conformation of the curved surface it is desired to produce, such as a parabola, hyperbola, sphere, or the like, said guide-bar acting as a run-way for the wheel or pulley 7. If it is desired to grind an interior, instead of an exteriorsurface, as shown in the drawings, this guide-bar should be reversed in position, as shown in dotted lines in Fig. 7, the bearing relations of the guidebar and the pulley 7 being of course correspondingly changed, which is easily eilected by arranging the pulley 7 a little lower down on the tool-holder arm 5. It will also be necessary to so locate the pulley 12 and its tension weight 14 as to reverse their action for this change. The operation of this form of the device is as follows: The surface to be operated upon is placed on the holder 2, and the revolution of the screw 52 causes the carriage 4 to travel as already described. As

the carriage moves transversely to the axis of rotation of the table or holder 2, the pulley 7 is caused to advance over the curved guide-bar 22 which has the form of the curve of said surface, and gives, therefore, to the tool-holding arm 5 and the toola forward and upward motion which is of the parabolic or other form corresponding to that of the sur face on the holder 2, the movement of the pulley and the tool being such as to cause the latter to travel in the curve named in the same manner as was described in connection with the device shown in Fig. 2 and in the description of the diagram shown in Fig. 1. In this form of the device, as well as in that shown in Fig. 2, the object to be acted upon is given a rotary motion simultaneously with the advance of the tool carriage through the agency of the holder 2, axis 1, and the pulley sustained by said axis, so that the surface acted upon by said tool assumes the form of a perfect parabola, or whatever other surface it is desired to produce.

Instead of using the pulley 7 the direction of motion of the tool holding arm 5 may be regulated by a lug 24 which has bearing on the under surface of the curved guide-way 22. In this case, however, theform of grinding tool shown in Figs. 5 and 6 should be used.

We do not limit ourselves to the special form of mechanism hereinafter described for accomplishing the construction of perfect paraboloidal surfaces, as we believe it is broadly new with us to give simultaneous motion to a cutting tool in two directions in such a manner as to cause it to assume the desired curvilinear motion and to simultaneously rotate a surface to be acted upon by said cutting tool during the time that it is passing through the described curve and our claim is therefore directed broadly to the application of this generic principle without relation to any special form of mechanism. It is obvious also that our apparatus may be changed so as to cut or grind solid surfaces of various curvilinear forms, such matters being well Within the skill'of those familiar with all kinds of analogous curved surfaces.

Having thus described our invention, what we claim, and desire to secure by Letters Patent of the United States, is

1. In a machine for grinding and polishing curved surfaces, the combination of a holder for the surface to be operated upon, means for rotating said holder, a tool holder, and mechanism for imparting movement to the tool simultaneously in two directions, one being a movement transversely to the axis of rotation of the surface to be operated upon, and the other being in the direction of the curve of the surface; substantially as described. g

2. Ina machine for grinding and polishing curved surfaces, the combination of a rotating holder for the surface to be operated upon, a carriage for the tool holder, mechanism for causing said carriage to travel in a direction transverse to the axis of rotation of said surface, and mechanism for imparting to the tool a movement in relation to the carriage so as to cause it to follow the outline of the curve; substantially as described.

3., In a machine for grindingand polishing curved surfaces, the combination of a holder for the surface to be operated upon, a carriage for the tool-holder, a tool movable with relation to said carriage in the direction of the curve of said surface, mechanism for causing the carriage to travel across the face of said surface, and a guide for causing the-tool to follow the outline of the curve of the surface as the carriage travels, said guide consisting of a flexible baud having one end secured to a fixed part of the machine, and the other end passing over a projection of the tool holder and secured to the movable carriage; substantially as described.

4. In a machine for grinding and polishing curved surfaces, the combination of a rotating table or holder for the surface to be 0perated upon, a carriage forthe tool holder, mechanism for causing said carriage to travel in a direction transverse to the axis of rotation of the surface, a tool movable in said carriage in a direction transverse to the move ment of the carriage, a disk fixed to the frame of the machine in the line of the axis of the rotating surface holder, a flexible band secured to said disk at one end, and having its other end secured to the carriage, a projection on the movable tool holder bearing against the under side of the band, and a weight or counterbalance to keep the projection in contact with the band and the band in proper tension; substantially as described.

5. In a machine for grinding and polishing curved surfaces, the combination of a rotating holder for the surface to be operated upon, a carriage for the tool holder, mechanism for causing said carriage to travel in a direction transverse to the axis of rotation of the surface, a tool movable in said carriage in a direction transverse to the movement of the carriage, a guide for causing the tool to follow the outline of the curve of the surface as the carriage travels, and a weight or counterbalance for the tool holder; substantially as described.

6. In a machine for grinding andpolishing curved surfaces, the combination of a tool holder, a tool, and a universal joint connecting said tool to the holder, said joint consisting of bearings 16, 17, 18, 19; substantially as described.

7. In a machine for grinding and polishing curved surfaces, the combination of a tool holder, a tool, a universal joint connecting the tool with the holder, said joint consisting of the bearings 16, 17, 18 and 19, and yielding springs 21 for adjusting the tool to the surface to be operated upon; substantially as described.

In testimony whereof We have hereunto subscribed our names this 2d day of December, 1893.

SIGMUND SOHUOKERT. GEORG MUNKER. Witnesses as to Sigmund Schuckert:

ALVESTO S. HOGUE, SOPHIE SOHUOKERT. Witnesses as to Geo. Munker:

THEODORE SToR'r, FRIEDRICH BIERLEIN. 

